METHOD FOR PREPARING A COMPOSITE MATERIAL, AND COMPOSITE MATERIAL PRODUCED FROM WASTE MDF AND/OR MDP STRUCTURED IN A PVC MATRIX

摘要

The composite material comprises waste MDF and/or MDP homogenised and distributed in a matrix of PVC resin, waste PVC, and additives. The composite material comprises 30-95% by weight PVC resin and 5-70% by weight waste MDF and/or MDP. The PVC resin has the following composition in percentages by weight: 40.0-98.3% injection-moulding PVC resin, 0.5-37.7% low molecular weight PVC resin or waste PVC, 0.7-6.0% thermal stabiliser, 0.1-1.0% external lubricant, 0.1-1.0% auxiliary processing agent, 0.1-15.0% plasticiser. Alternatively, the PVC resin composition can comprise 0.1-8% by weight expanding agent. The granulometric range of the waste MDF and/or MDP is comprised between 50 and 250 micrometres. The method for preparing the composite material comprises a first step in which a premix of PVC resins and additives is prepared, a second mixing and cooling step, a third step in which the waste MDF and/or MDP are mixed with the premix, and a fourth step in which the thus prepared compound is injection-moulded or extruded to produce the composite product. Optionally, the method can include a fifth step which consists in recycling the defective extruded or injection-moulded products, by feeding them to grinders, and the ground waste is used in the form of a powder during the third step.